JP2012239814A - Radiographic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent image quality deterioration during imaging irrespectively of the presence of a power reception function.SOLUTION: A power supply device 91 supplies power for charging a built-in battery 41 of an electronic cassette in a non-contact state. When a detachment/attachment detection part detects that the cassette is mounted on a holder of an imaging table, an inquiry signal is transmitted from a power supply coil 92 under control of a power supply control part 97. When the cassette having no power reception function in the holder is mounted and when a response signal is not received for a predetermined time from the start of transmission of the inquiry signal, the transmission of the inquiry signal is stopped by the power supply control part 97.

Description

  The present invention relates to a radiation imaging apparatus.

  Recently, in the field of radiography, for example, X-ray imaging, X-ray image detection apparatuses using a flat panel detector (FPD) as a detector instead of an X-ray film or an imaging plate (IP) have become widespread. Yes. In the FPD, pixels that accumulate signal charges corresponding to the amount of incident X-rays are arranged in a matrix. The FPD accumulates signal charge for each pixel, converts the accumulated signal charge into a voltage signal by a signal processing circuit, detects an X-ray image representing the image information of the subject, and uses this as digital image data Output.

  An electronic cassette (portable X-ray image detection apparatus) in which an FPD is built in a rectangular parallelepiped housing has also been put into practical use. The electronic cassette is used by attaching it to an existing imaging table or dedicated imaging table for film cassette, IP cassette, and CR cassette. It can be used by itself. In addition, in order to take pictures of elderly people who are being treated at home or those who are suddenly ill due to accidents, disasters, etc., they may be taken out of hospitals where there is no equipment for taking pictures.

  There is a type of electronic cassette that has a built-in battery to cover the drive power of each unit and exchanges signals with the imaging control device by wireless communication. In such a type, the battery can be taken out from the electronic cassette and set in a dedicated cradle for charging, or the electronic cassette itself can be set in the cradle and charged while the battery is built in the electronic cassette.

  In addition, an electromagnetic induction type or magnetic resonance type non-contact power feeding device is provided near the electronic cassette, and power for charging a battery in the electronic cassette is supplied from the non-contact power feeding device (patent). Reference 1). In Patent Document 1, photographing is prohibited during non-contact power feeding in order to prevent noise caused by non-contact power feeding from being superimposed on an image and degrading the image quality. It is described that a weak magnetic field is applied from a power supply device in order to detect the presence of an electronic cassette.

JP 2010-250292 A

  As described above, the electronic cassette can be attached to an existing photographing stand. If you turn it over, you can share a single photographic stand with a wide variety of cassettes, including electronic cassettes that do not have a power receiving function (including electronic cassettes made by other companies, in-house manufactured power cassettes, IP cassettes, and CR cassettes). It is possible to do so, even in the actual medical field. Under such special circumstances, the battery charging power supply device of the electronic cassette is required to be able to take an image without any trouble even in a cassette having a power receiving function or a cassette having no power receiving function.

  In the method of detecting the presence of an electronic cassette by applying a weak magnetic field from a power supply device as in Patent Document 1, there is no way to respond by receiving a magnetic field if the cassette has no power receiving function. The magnetic field is continuously output from the power feeding device without returning a response. When photographing is performed in this state or image data is transmitted to an external device, image quality deterioration due to noise occurs. If the image quality is severely deteriorated, the image must be taken again, and the amount of exposure of the subject increases accordingly.

  In particular, an electronic cassette uses a highly sensitive FPD so that even a weak electromagnetic wave can be detected in order to reduce the exposure amount of the subject. When an electronic cassette having no power receiving function is used, there is a concern that the magnetic field from the power feeding device becomes noise and image unevenness at a level that cannot be ignored. Also in the CR cassette, the behavior of the phosphor molecules may be adversely affected by the Lorentz force due to the magnetic field.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to enable photographing without causing image quality deterioration even in a cassette having neither a power receiving function nor a cassette having a power receiving function.

  In order to achieve the above object, a radiographic apparatus according to the present invention includes a radiographic electronic cassette having a built-in battery, and a power supply that supplies power for charging in a non-contact manner to the battery built in the electronic cassette. A signal transmitting means for transmitting an inquiry signal for searching for the electronic cassette having a power receiving function to be fed, a signal receiving means for receiving a response signal to the inquiry signal from the electronic cassette, and the signal receiving means When a response signal is not received for a certain period of time, a power supply device having a control unit that causes the signal transmission unit to stop transmission of an inquiry signal and an external control unit that comprehensively controls the operation of the electronic cassette are provided. And

  It is preferable to provide installation detection means for detecting whether an electronic cassette having a power receiving function or another cassette not having a power receiving function is installed at a designated location. The signal transmission unit starts transmission of an inquiry signal when installation is detected by the installation detection unit. The installation detection means detects whether or not an electronic cassette having a power receiving function or another cassette not having a power receiving function is attached to the holder of the photographing stand. In other words, the “designated location” in this case is the holder of the photographing stand.

  The signal transmitting means starts transmitting an inquiry signal when the receiving means receives that the electronic cassette having the power receiving function or another cassette not having the power receiving function is turned on. It may be when the receiving means has received that the imaging conditions have been input from the external device using an electronic cassette having a power receiving function or another cassette having no power receiving function.

  It is preferable to provide storage means for storing and holding the reception history of the response signal of the signal receiving means indicating whether it is an electronic cassette having a power receiving function or another cassette not having a power receiving function regardless of power on / off. In this case, if the installation detection unit does not detect the replacement of the cassette from the power-off to the power-on of the power supply device, the drive is controlled according to the storage contents of the storage unit, and the installation detection unit from the power-off to the power-on again. When the exchange of the cassette is detected, the transmission of the inquiry signal by the signal transmission means is started. The storage means is preferably provided in the external control device.

  The signal transmitting means and the signal receiving means are antennas, and transmit and receive electromagnetic waves as inquiry signals and response signals.

  It is preferable to stop the power supply when the reception unit receives information indicating that radiographic image data is being transmitted from the electronic cassette to the external device during imaging with the electronic cassette. It is also preferable to stop power feeding when it is detected that the battery is fully charged or when it is detected that the electronic cassette has been removed from the holder of the photographing stand.

  It is preferable that the power supply device is built in a holder of an imaging stand in which the electronic cassette having a power receiving function or another cassette not having a power receiving function is detachably accommodated.

  According to the present invention, since an inquiry signal for searching for an electronic cassette having a power receiving function to be supplied is stopped in a predetermined time, even a cassette having neither a power receiving function nor a cassette can be photographed without causing image quality deterioration.

It is the schematic which shows the structure of a X-ray imaging system. It is a perspective view which shows the structure of an electronic cassette. It is a figure which shows the electrical structure of an electronic cassette and FPD. It is a figure which shows the structure of the electric power receiving function of an electric power feeder and an electronic cassette. It is a flowchart which shows the operation | movement procedure of an electric power feeder. It is a flowchart which shows the operation | movement procedure of an electric power feeder. It is a figure which shows the electric power feeder which provided the non-volatile memory.

  In FIG. 1, the X-ray imaging system 10 includes an X-ray generation device 11 and an X-ray imaging device 12. The X-ray generator 11 includes an X-ray source 13, a radiation source controller 14 that controls driving of the X-ray source 13, and an irradiation switch 15. The X-ray source 13 includes an X-ray tube 13a that emits X-rays, and an irradiation field limiter (collimator) 13b that limits an X-ray irradiation field emitted by the X-ray tube 13a.

  The X-ray tube 13a includes a cathode made of a filament that emits thermoelectrons, and an anode (target) that emits X-rays when the thermoelectrons emitted from the cathode collide. The target has a disk shape, and is a rotating anode in which the focal point moves on a circular orbit by rotation, and the heat generated at the focal point where thermal electrons collide is dispersed. The irradiation field limiter 13b has a plurality of lead plates that shield X-rays arranged in a cross-beam shape, and an irradiation opening that transmits X-rays is formed in the center. By moving the position of the lead plate, The irradiation field is limited by changing the size of the irradiation opening.

  The radiation source control device 14 determines a high voltage generator that supplies a high voltage to the X-ray source 13, a tube voltage that determines the energy spectrum of the X-rays that the X-ray source 13 irradiates, and an irradiation amount per unit time. It consists of a controller that controls the tube current and the X-ray irradiation time. The high voltage generator boosts the input voltage with a transformer to generate a high voltage tube voltage, and supplies driving power to the X-ray source 13 through the high voltage cable 16. The X-ray generation apparatus 11 of this example does not have a communication function with the X-ray imaging apparatus 12, and radiographers can set imaging conditions such as tube voltage, tube current, and irradiation time through the operation panel of the radiation source control apparatus 14. Set manually.

  The irradiation switch 15 is operated by a radiologist and is connected to the radiation source control device 14 by a signal cable 17. The irradiation switch 15 is a two-stage push switch, which generates a warm-up start signal for starting the warm-up of the X-ray source 13 by pressing the single stage, and for starting the irradiation of the X-ray source 13 by pressing the two-stage. The irradiation start signal is generated. These signals are input to the radiation source controller 14 through the signal cable 17.

  The radiation source control device 14 controls the operation of the X-ray source 13 based on a control signal from the irradiation switch 15. When the warm-up start signal is received, the radiation source control device 14 activates the heater to preheat the filament, and also starts the rotation of the target to reach the target rotational speed. The time required for warm-up is about 200 msec to 1500 msec. The radiologist inputs a warm-up start instruction by pressing the irradiation switch 15 in one stage, and then inputs the irradiation start instruction by pressing in two stages after a necessary interval for warm-up.

  When receiving the irradiation start signal, the radiation source control device 14 starts supplying power to the X-ray source 13 and activates a timer to start measuring the X-ray irradiation time. Then, when the irradiation time set in the imaging conditions has elapsed, X-ray irradiation is stopped. Although the X-ray irradiation time varies depending on the imaging conditions, in the case of still image shooting, the maximum X-ray irradiation time is often set to a range of about 500 msec to about 2 s, and the irradiation time Is set with this maximum irradiation time as the upper limit.

  The X-ray imaging apparatus 12 includes an electronic cassette 21, a standing position imaging table 22 a, a lying position imaging table 22 b, an imaging control device 23, and a console 24. The electronic cassette 21 includes an irradiation detection sensor 25, an FPD 26 (see also FIGS. 2 and 3), and a portable housing 27 (see FIG. 2) that accommodates the FPD 26, and is irradiated from the X-ray source 13. Upon receiving X-rays transmitted through the subject H, an X-ray image is output. The electronic cassette 21 has a substantially rectangular shape and a flat shape, and the plane size is substantially the same size as the film cassette, the IP cassette, and the CR cassette (a size based on the international standard ISO 4090: 2001).

  The irradiation detection sensor 25 is disposed in the vicinity of the imaging surface 28 (see FIG. 3) of the FPD 26. The irradiation detection sensor 25 receives the X-ray irradiation and outputs an irradiation detection signal corresponding to the incident amount of the X-ray. The irradiation detection signal is input to the imaging control device 23 by the composite cable 29 or wirelessly. The imaging control device 23 monitors the signal level of the irradiation detection signal and detects that X-ray irradiation by the X-ray source 13 has started.

  The standing position imaging table 22a and the recumbent imaging table 22b have holders 30a and 30b to which the electronic cassette 21 can be detachably attached, respectively, and the imaging surface 28 on which X-rays are incident faces the X-ray source 13. The electronic cassette 21 is held. In the figure, a state in which photographing is performed on the standing photographing stand 22a is shown. The X-ray source 13 can be moved within a predetermined range in the imaging room by a moving mechanism (not shown) made of rails or the like laid on the ceiling of the imaging room, and is shared by the standing imaging table 22a and the standing imaging table 22b. Is done.

  Since the size of the casing 27 is substantially the same as that of the film cassette, the IP cassette, and the CR cassette, the electronic cassette 21 can be attached to an existing photographing stand for the film cassette, the IP cassette, and the CR cassette. In other words, it is also possible to use a film cassette, an IP cassette, or a CR cassette attached to each photographing base 22a, 22b. A plurality of electronic cassettes 21 are provided in one room, for example, two for each of the imaging tables 22a and 22b. The electronic cassette 21 can be used as a single unit by being placed on the bed on which the subject H is supine or being held by the subject itself, instead of being set on the standing position photographing stand 22a or the lying position photographing stand 22b. It is.

  The imaging control device 23 is connected to the electronic cassette 21 so as to be communicable by a wired method using a composite cable 29 or a wireless method using an antenna 31 (see FIG. 2 and the like), and controls the electronic cassette 21. Specifically, the imaging conditions are transmitted to the electronic cassette 21 to set the signal processing conditions (such as the gain of the amplifier 74) of the FPD 26, and the operation of the FPD 26 is indirectly controlled. The image data from 21 is transmitted to the console 24.

  The imaging control device 23 communicates with the CPU 23a that centrally controls the device, the electronic cassette 21 by a wired method or a wireless method, and a communication unit 23b that communicates with the console 24 via the communication cable 32, and a memory 23c. Have. The communication unit 23b and the memory 23c are connected to the CPU 23a. The memory 23c stores a control program executed by the CPU 23a.

  The console 24 transmits imaging conditions to the imaging control device 23 and performs various image processing such as offset correction and gain correction on the X-ray image data transmitted from the imaging control device 23. In addition to being displayed on the display of the console 24, the processed X-ray image is stored in a data storage device such as a hard disk or memory in the console 24 or an image storage server connected to the console 24 via a network.

  The console 24 receives an input of an examination order including information such as the patient's sex, age, imaging region, and imaging purpose, and displays the examination order on the display. The examination order is input from an external system that manages patient information such as HIS (Hospital Information System) and RIS (Radiation Information System) and examination information related to radiation examination, or is manually input by a radiographer. The radiologist confirms the contents of the examination order on the display, and inputs imaging conditions corresponding to the contents through the operation screen of the console 24.

  2 and 3, the electronic cassette 21 includes an antenna 31 and a battery 41, and wireless communication with the imaging control device 23 is possible. The battery 41 supplies power for operating each part of the electronic cassette 21. A relatively small battery 41 is used so as to fit in the thin electronic cassette 21. The battery 41 can be charged with electric power from a power supply device 91 (see FIG. 4) built in the holders 30a and 30b of the imaging tables 22a and 22b. Further, the battery 41 can be taken out by opening the lid 42 provided on one side of the electronic cassette 21 and can be taken out from the electronic cassette 21 and set in a dedicated cradle for charging. . The antenna 31 transmits and receives radio waves for wireless communication to and from the imaging control device 23.

  The electronic cassette 21 is provided with a socket 43 in addition to the antenna 31. The socket 43 is disposed on one side surface of the electronic cassette 21 opposite to the lid 42. The socket 43 is provided for wired connection with the imaging control device 23, and the connector 44 of the composite cable 29 connected to the imaging control device 23 is inserted into the socket 43. The composite cable 29 is used when wireless communication between the electronic cassette 21 and the imaging control device 23 becomes impossible due to a shortage of the remaining amount of the battery 41 or the like. When the connector 44 is inserted into the socket 43 and the composite cable 29 is used, wired communication with the imaging control device 23 becomes possible and power can be supplied from the imaging control device 23 to the electronic cassette 21.

  The antenna 31 and the socket 43 are connected to the communication unit 45. The communication unit 45 mediates transmission / reception of various information and signals including image data between the antenna 31 or the socket 43 and the control circuit 46 and the memory 47.

  The FPD 26 includes a TFT active matrix substrate, and includes an imaging surface 28 formed by arranging a plurality of pixels 52 that accumulate signal charges corresponding to the amount of incident X-rays on the substrate. The plurality of pixels 52 are two-dimensionally arranged in a matrix of n rows (x direction) × m columns (y direction) at a predetermined pitch.

  The FPD 26 further includes a scintillator (phosphor) that converts X-rays into visible light, and is an indirect conversion type in which visible light converted by the scintillator is photoelectrically converted by the pixels 52. The scintillator is made of CsI (cesium iodide), GOS (gadolinium oxysulfide), or the like, and is disposed so as to face the entire imaging surface 28 on which the pixels 52 are arranged. Note that a direct conversion type FPD using a conversion layer (such as amorphous selenium) that directly converts X-rays into electric charges may be used.

  The pixel 52 includes a photodiode 64 that is a photoelectric conversion element that generates charges (electron-hole pairs) upon incidence of visible light, a capacitor (not shown) that accumulates charges generated by the photodiode 64, and a switching element. A thin film transistor (TFT) 65 is provided.

  The photodiode 64 has a structure in which a semiconductor layer (for example, PIN type) that generates electric charge and an upper electrode and a lower electrode are arranged above and below the semiconductor layer. The photodiode 64 has a TFT 65 connected to the lower electrode and a bias line 66 connected to the upper electrode. The bias line 66 is provided by the number of rows (n rows) of the pixels 52 in the imaging surface 28 and connected. It is bound to 67. The connection 67 is connected to a bias power source 68. A bias voltage Vb is applied from the bias power source 68 to the upper electrode of the photodiode 64 through the connection 67 and the bias line 66. An electric field is generated in the semiconductor layer by application of the bias voltage Vb, and charges (electron-hole pairs) generated in the semiconductor layer by photoelectric conversion are applied to the upper and lower electrodes, one having a positive polarity and the other having a negative polarity. The electric charge is accumulated in the capacitor.

  The TFT 65 has a gate electrode connected to the scanning line 69, a source electrode connected to the signal line 70, and a drain electrode connected to the photodiode 64. The scanning lines 69 and the signal lines 70 are wired in a grid pattern. The scanning lines 69 are the number of rows of the pixels 52 (n rows) in the imaging surface 28, and the signal lines 70 are the number of columns of the pixels 52 (m columns). Min) each is provided. The scanning line 69 is connected to the gate driver 62, and the signal line 70 is connected to the signal processing circuit 63.

  The gate driver 62 drives the TFT 65 to accumulate a signal charge corresponding to the incident amount of X-rays in the pixel 52, a read (reading) operation for reading the signal charge from the pixel 52, and a reset (empty reading). ) Make an action. The control circuit 46 controls the start timing of each operation performed by the gate driver 62.

  In the accumulation operation, the TFT 65 is turned off, and signal charges are accumulated in the pixel 52 during that time. In the read operation, gate pulses G1 to Gn for simultaneously driving the TFTs 65 in the same row are generated sequentially from the gate driver 62, the scanning lines 69 are sequentially activated one by one, and the TFTs 65 connected to the scanning lines 69 are one row at a time. Turn on. The charge accumulated in the capacitor of the pixel 52 is read out to the signal line 70 and input to the signal processing circuit 63 when the TFT 65 is turned on.

  Dark charges are generated in the semiconductor layer of the photodiode 64 regardless of whether X-rays are incident. This dark charge is accumulated in the capacitor because the bias voltage Vb is applied. Since the dark charge generated in the pixel 52 becomes a noise component for the image data, a reset operation is performed to remove this. The reset operation is an operation for sweeping out dark charges generated in the pixels 52 through the signal line 70.

  For example, the reset operation is performed by a sequential reset method in which the pixels 52 are reset row by row. In the sequential reset method, similarly to the signal charge reading operation, gate pulses G1 to Gn are sequentially generated from the gate driver 62 to the scanning line 69 to turn on the TFTs 65 of the pixels 52 one row at a time. While the TFT 65 is on, dark charge flows from the pixel 52 to the integrating amplifier 71 through the signal line 70. In the reset operation, unlike the read operation, the charge accumulated in the integrating amplifier 71 is not read by the multiplexer (MUX) 72, and the reset pulse RST is generated from the control circuit 46 in synchronization with the generation of the gate pulses G1 to Gn. Is output, and the integrating amplifier 71 is reset.

  Instead of the sequential reset method, multiple rows of array pixels are grouped as a group, and the reset is performed sequentially within the group, and the dark charge of the number of rows in the group is simultaneously discharged. An all-pixel reset method that simultaneously sweeps out the dark charges may be used. The reset operation can be speeded up by a parallel reset method or an all-pixel reset method.

  The signal processing circuit 63 includes an integrating amplifier 71, a MUX 72, an A / D converter 73, and the like. The integrating amplifier 71 is individually connected to each signal line 70. The integrating amplifier 71 includes an operational amplifier and a capacitor connected between the input and output terminals of the operational amplifier, and the signal line 70 is connected to one input terminal of the operational amplifier. The other input terminal of the integrating amplifier 71 is connected to the ground (GND). The integrating amplifier 71 integrates the charges input from the signal line 70, converts them into voltage signals D1 to Dm, and outputs them. The MUX 72 is connected to the output terminal of the integration amplifier 71 in each column via an amplifier 74 and a sample hold (S / H) unit 75. An A / D converter 73 is connected to the output side of the MUX 72.

  The MUX 72 sequentially selects one integration amplifier 71 from a plurality of integration amplifiers 71 connected in parallel, and serially inputs voltage signals D1 to Dm output from the selected integration amplifier 71 to the A / D converter 73. . The A / D converter 73 converts the input voltage signals D1 to Dm into digital data and outputs the digital data to the memory 47 built in the housing 27 of the electronic cassette 21. An amplifier may be connected between the MUX 72 and the A / D converter 73.

  When the voltage signal D1 to Dm for one row is read from the integrating amplifier 71 by the MUX 72, the control circuit 46 outputs a reset pulse RST to the integrating amplifier 71 and turns on the reset switch 71a of the integrating amplifier 71. As a result, the signal charge for one row accumulated in the integrating amplifier 71 is reset. When the integrating amplifier 71 is reset, the gate pulse of the next row is output from the gate driver 62, and reading of the signal charges of the pixels 52 of the next row is started. These operations are sequentially repeated to read the signal charges of the pixels 52 in all rows.

  When the reading of all rows is completed, image data representing an X-ray image for one screen is recorded in the memory 47. The image data is read from the memory 47 and output to the imaging control device 23 through the communication unit 45. Thus, an X-ray image of the subject H is detected.

  In the FPD 26, the irradiation detection sensor 25 detects the start of X-ray irradiation while repeatedly performing the reset operation. When the X-ray irradiation start is detected by the irradiation detection sensor 25, the control circuit 46 shifts the operation of the FPD 26 from the reset operation to the accumulation operation. The control circuit 46 measures the elapsed time from the start of the accumulation operation using a timer. When the elapsed time reaches the time set in the shooting conditions, the FPD 26 is shifted from the accumulation operation to the reading operation. Alternatively, the end of X-ray irradiation may be detected by the irradiation detection sensor 25 without using a timer, and the FPD 26 may be shifted from the accumulation operation to the reading operation.

  The electronic cassette 21 is a minimum such as the communication unit 45 and the charging circuit 82 (see FIG. 4) from the end of imaging of a certain patient to transmission of image data to the imaging control device 23 until the start of the next imaging (between imaging). It operates in the sleep mode that supplies power only to the necessary parts and stops power supply to other parts to reduce power consumption. When the electronic cassette 21 receives an imaging condition from the imaging control device 12, the electronic cassette 21 supplies power to each unit other than the communication unit 45 and the charging circuit 82 to operate the FPD 26 and can immediately output an X-ray image. Transition from the sleep mode to the preparation mode. When the imaging preparation mode is entered, the FPD 26 repeats the reset operation and waits for detection of the start of X-ray irradiation.

  In FIG. 4, the electronic cassette 21 is provided with a power receiving coil 81, and a charging circuit 82 is connected to the power receiving coil 81. The charging circuit 82 includes an AC / DC converter (rectifier) and a DC regulator, converts AC power received by the power receiving coil 81 into DC power, and outputs a voltage suitable for charging the battery 41. The operations of the power reception coil 81 and the charging circuit 82 are controlled by the power reception control unit 83.

  A power feeding device 91 is built in the holders 30a and 30b of the photographing bases 22a and 22b. The power supply device 91 includes a power supply coil 92, and an AC power supply 94 is connected to the power supply coil 92 via a power supply circuit 93 including a rectifier. The feeding coil 92 faces the power receiving coil 81 provided on the electronic cassette 21 side when the electronic cassette 21 is set in the holders 30a and 30b, and is provided at a position where the distance from the power receiving coil 81 is about several millimeters. Yes. The power supply coil 92 performs electromagnetic induction type non-contact power supply to the power receiving coil 81.

  The holders 30 a and 30 b are provided with a full charge detection unit 95 and an attachment / detachment detection unit (installation detection means) 96. The full charge detection unit 95 detects whether or not the battery 41 is fully charged, and the attachment / detachment detection unit 96 does not have an electronic cassette 21 having a power reception function, another electronic cassette having no power reception function, or a power reception function. It is detected whether a cassette that can be attached to the holders 30a, 30b, such as a film cassette, an IP cassette, or a CR cassette, is attached to the holders 30a, 30b. Each of the detection units 95 and 96 outputs a detection result to the power supply control unit 97. The power supply control unit 97 controls the operation of the power supply coil 92 and the power supply circuit 93 in response to the detection results of the detection units 95 and 96.

  Specifically, when the full charge detection unit 95 detects that the battery 41 is fully charged, and when the attachment / detachment detection unit 96 detects that the cassette has been removed from the holders 30a and 30b, the feeding coil 92 And the AC power supply 94 are disconnected, or the drive of the AC power supply 94 is stopped and the power supply is interrupted. Further, imaging is performed by detecting the start of X-ray irradiation by the irradiation detection sensor 25, and power supply is interrupted until the image transmission is completed and the mode is shifted to the sleep mode. The power supply control unit 97 supplies power only during the transition to the sleep mode between the above-described imaging in which neither imaging nor image transmission is performed, and until the irradiation detection sensor 25 detects the start of X-ray irradiation. Non-contact power feeding by the coil 92 is performed.

  As a method for detecting whether or not the battery 41 is fully charged by the power supply device 91, means for monitoring the discharge voltage of the battery 41 and measuring the amount of charge is provided on the electronic cassette 21 side, and the measurement result is displayed on the electronic cassette. 21 is wired or wirelessly transmitted to the power supply apparatus 91, or the current flowing through the power supply coil 92 and the AC power supply 94 is measured on the power supply apparatus 91 side, and whether or not the battery 41 is fully charged is determined according to the measurement result. There is a method for determination, and either method may be adopted.

  Further, as a method for detecting whether or not the cassette is mounted on the holders 30a and 30b, for example, a sensor (reflection-type optical sensor) that optically, mechanically, or electrically detects attachment / detachment of the cassette to / from the holders 30a and 30b. , An ultrasonic sensor, a limit switch, an electromagnetic wave sensor, etc.), and the output of the sensor is transmitted to the power feeding device 91 via the imaging control device 23 or the console 24, or a discrete (single function) semiconductor as the attachment / detachment detection unit 96 It is possible to employ a method in which a dedicated circuit configured by the above is provided and transmitted directly from the circuit to the power feeding device 91.

  Whether the irradiation detection sensor 25 detects the start of X-ray irradiation and whether image data is being transmitted is input from the imaging control device 23 to the power supply control unit 97 of the power supply device 91 by wire or wirelessly. The Alternatively, as in an inquiry signal and a response signal, which will be described later, whether the irradiation detection sensor 25 has detected the start of X-ray irradiation between the power receiving coil 81 and the power feeding coil 92 and whether image data is being transmitted. A signal indicating that may be exchanged. That is, the power supply control unit 97 or the power supply coil 92 corresponds to a receiving unit. Upon receipt of these signals, the power supply control unit 97 detects the start of X-ray irradiation by the irradiation detection sensor 25 as described above, and then performs imaging until image transmission ends and the mode shifts to the sleep mode. During this period, power supply is interrupted.

  The power supply device 91 is turned on in conjunction with the power-on of the imaging control device 23. Alternatively, the power is turned on manually by operating a power switch. When the signal indicating that the cassette is mounted on the holders 30a and 30b is received from the attachment / detachment detection unit 96 after the power is turned on, the power supply control unit 97 intermittently supplies a weak current to the power supply coil 92. 93 operation is controlled. The weak magnetic field generated by passing a weak current through the feeding coil 92 is used to determine whether or not the cassette mounted on the holders 30a and 30b has a power receiving function. .

  When the electronic cassette 21 having a power receiving function is attached to the holders 30a and 30b, the power receiving coil 81 receives an inquiry signal. As in the case of the inquiry signal, the power reception control unit 83 causes a weak current to flow through the power receiving coil 81 to generate a weak magnetic field, and transmits this as a response signal to the inquiry signal. When the response signal is received by the power supply coil 92, the power supply control unit 97 stops the transmission of the inquiry signal. By receiving the response signal, the power supply control unit 97 recognizes that the cassette attached to the holders 30a and 30b is the electronic cassette 21 having a power receiving function, and starts non-contact power supply through the power supply coil 92.

  On the other hand, when the holders 30a and 30b are equipped with other electronic cassettes that do not have a power receiving function, or film cassettes, IP cassettes, and CR cassettes that do not have a power receiving function, the response signal to the inquiry signal is naturally a cassette. Not sent from. The same applies to the case where the electronic cassette 21 is not in a state capable of transmitting a response signal due to a failure of the power receiving coil 81 or the like. If the inquiry signal is continuously output in such a case, the inquiry signal becomes noise that causes image quality deterioration for other electronic cassettes that do not have a power receiving function or cassettes that do not have a power receiving function.

  Therefore, the power supply control unit 97 activates a built-in timer from the start of transmission of the inquiry signal, and stops transmission of the inquiry signal when a response signal is not received for a predetermined time (for example, 15 seconds) counted by the timer. Alternatively, the transmission of the inquiry signal may be stopped when the response signal is not received even if the inquiry signal is transmitted a predetermined number of times. When the attachment / detachment detection unit 96 detects that the cassette has been attached to the holders 30a and 30b after the attachment / detachment detection unit 96 has once detected that the cassette has been removed from the holders 30a and 30b. Do not send inquiry signals until.

  Hereinafter, the operation of the above configuration will be described with reference to the flowcharts of FIGS. 5 and 6. When imaging is performed by the X-ray imaging system 10, first, the height and height of the electronic cassette 21 set on the imaging table 22 in either the standing position or the standing position are adjusted, and the imaging region and position of the subject H are adjusted. Adjust. Further, the height of the X-ray source 13 and the size of the irradiation field are adjusted according to the height of the electronic cassette 21 and the size of the imaging region. Next, the power of the electronic cassette 21 is turned on. Further, as shown in step 10 (S10) of FIG. 5, the power supply device 91 is turned on. The electronic cassette 21 starts up in the sleep mode. Subsequently, shooting conditions are input from the console 24, and shooting conditions are set in the electronic cassette 21 via the shooting control device 23. The electronic cassette 21 shifts from the sleep mode to the shooting preparation mode. The imaging conditions are also set in the radiation source control device 14.

  After the power is turned on, the power supply control unit 97 of the power supply apparatus 91 monitors the detection result from the attachment / detachment detection unit 96. When a signal indicating that the cassette is attached to the holders 30a and 30b is input from the attachment / detachment detection unit 96 (YES in S11), an inquiry signal is transmitted from the power supply coil 92 under the control of the power supply control unit 97 ( S12).

  When the electronic cassette 21 having a power receiving function is attached to the holders 30a and 30b, an inquiry signal is received by the power receiving coil 81, and a response signal to the inquiry signal is transmitted from the power receiving coil 81 under the control of the power receiving control unit 83. Is done. The response signal is received by the power feeding coil 92 (YES in S13), and the power feeding device 91 starts the electromagnetic induction type non-contact power feeding through the power feeding coil 92 to the power receiving coil 81 (S14).

  On the other hand, when the cassette having no power receiving function is attached to the holders 30a and 30b and the response signal is not received for a predetermined time from the start of transmission of the inquiry signal (NO in S13, YES in S15), the power supply control unit 97 Transmission of the inquiry signal is stopped (S16), and then the non-contact power supply function by the power supply coil 92 is also stopped (S17).

  When preparation for imaging is completed, the radiation switch 15 is pushed one step by the radiologist. As a result, a warm-up start signal is transmitted to the radiation source control device 14 and the warm-up of the X-ray source 13 is started. After a predetermined time has elapsed, the irradiation switch 15 is pushed in two steps, an irradiation start signal is transmitted to the radiation source control device 14, and X-ray irradiation is started.

  The FPD 26 detects whether or not X-ray irradiation has been started by the irradiation detection sensor 25 while performing a reset operation. When the start of X-ray irradiation is detected, the non-contact power supply by the power supply coil 92 is stopped (NO in S20 of FIG. 6, YES in S21, S22).

  When the start of X-ray irradiation is detected, the control circuit 46 turns off all the TFTs 65 and shifts to the accumulation operation. The radiation source control device 14 stops the X-ray irradiation when the irradiation time set in the imaging conditions has elapsed. Further, the FPD 26 also ends the accumulation operation after a lapse of a predetermined time corresponding to the irradiation time set in the imaging conditions, and shifts to a reading operation. In the read operation, the signal charges accumulated in the pixels 52 are read out row by row from the first row, and are recorded in the memory 47 as X-ray image data for one screen. This image data is transmitted to the console 24 via the imaging control device 23. After the read operation, the FPD 26 restarts the reset operation. Further, after the transmission of the image data, the non-contact power supply by the power supply coil 92 is resumed (NO in S20 of FIG. 6, NO in S21, S23).

  The image data is subjected to various image processing such as offset correction and gain correction at the console 24, and then displayed on the display of the console 24 or stored in a data storage device. The above series of operations is repeatedly executed until all scheduled shootings are completed.

  In FIG. 6, when the power supply device 91 is driven and the battery 41 is charged, the full charge detection unit 95 fully charges the battery 41, or the attachment / detachment detection unit 96 removes the electronic cassette 21 (single use). Is detected (YES in S20), the non-contact power supply function by the power supply coil 92 is stopped and charging of the battery 41 is interrupted regardless of whether X-ray irradiation is performed or image data is transmitted (S22). .

  As described above, according to the present invention, the inquiry signal issued from the power supply device 91 to search for the electronic cassette 21 having the power receiving function is stopped after a predetermined time has elapsed, so that the cassette having no power receiving function is the holder 30a, When used by being attached to 30b, it is possible to reliably prevent the inquiry signal from continuing to be output from the power receiving coil 81 and riding on the image data as noise and degrading the image quality.

  When the attachment / detachment detection unit 96 detects that the cassette is attached to the holders 30a and 30b, transmission of the inquiry signal is started, and if the response signal is not received within a certain time, the inquiry signal is automatically stopped. This saves the technician from having to manually stop the inquiry signal according to the type of cassette. The engineer can take a picture without worrying about whether the cassette has a power receiving function.

  Imaging is performed by detecting the start of X-ray irradiation by the irradiation detection sensor 25, and driving of the power supply device 91 is stopped until the image transmission is completed and the sleep mode is shifted, so that noise is superimposed on the image data. Electromagnetic compatibility (EMC) at the time of photographing or image transmission that is a concern can be ensured.

  In order to reduce the exposure amount of the subject, a highly sensitive detector is used for the FPD 26 so that even weak electromagnetic waves can be detected. For this reason, there is a high need for ensuring electromagnetic compatibility at the time of shooting and preventing image quality deterioration due to electromagnetic noise, and therefore the usefulness of the present invention is also extremely high.

  In the above embodiment, the power supply is stopped when the irradiation detection sensor 25 detects the start of X-ray irradiation, and the battery 41 is automatically switched between charging / non-charging without making the engineer aware of it. An operation switch for instructing charging / non-charging is provided in any of the imaging bases 22a and 22b, the power supply device 81, the imaging control device 23, and the console 24, and power supply is started or stopped in synchronization with the operation of the operation switch. May be.

  In the above-described embodiment, transmission of the inquiry signal is started when the attachment / detachment detection unit 96 detects that the cassette is mounted on the holders 30a and 30b, but in addition to or instead of this, the power source of the cassette is switched on. The transmission of the inquiry signal may be started when it is turned on. If the cassettes mounted on the holders 30a and 30b have a power receiving function, an inquiry signal cannot be received unless the power is turned on even if the cassettes are mounted. At the same time, the cassette is powered on as a condition for starting transmission of the inquiry signal.

  Alternatively, the transmission of the inquiry signal may be started when the shooting conditions are input from the console 24 and the shooting conditions are set in the electronic cassette 21 via the shooting control device 23. In short, if the shooting conditions are input through the console 24, an inquiry signal is transmitted before the cassettes are mounted on the holders 30a and 30b and shooting is performed, and the type of the cassette can be determined by stopping for a certain period of time, any trigger is possible. The inquiry signal transmission may be started at. It should be noted that the fact that the cassette has been turned on or that the imaging condition has been set for the electronic cassette 21 is received by the power supply control unit 97 via the imaging control device 23 or the like, or is exchanged between the power receiving coil 81 and the power supply coil 92. .

  In addition to the holder of the imaging stand, for example, a mark indicating the power supply possible area of the power supply device is provided on the bed, and it is detected whether a cassette is installed at the marked location, and the same processing as in the above embodiment May be performed.

  Note that, as in the power supply apparatus 101 illustrated in FIG. 7, a nonvolatile memory 102 that retains the stored contents even when the power supply apparatus 101 is turned off is provided, and a cassette for determining whether to have a power reception function by transmitting an inquiry signal is provided. The result of recognizing the type (response signal reception presence / absence) may be stored in the nonvolatile memory 102. Then, the attachment / detachment detection unit 96 is always driven by a power source different from that of the power supply apparatus 101, and it is monitored whether or not the cassette mounted between the power supply apparatus 91 and the power supply apparatus 91 is turned on again. Further, when the power supply device 101 is turned on again, the drive of the power supply device 101 is controlled in accordance with the stored contents of the nonvolatile memory 102.

  Specifically, when the cassette mounted from the time the power supply device 91 is turned off until the power is turned on has not been replaced, and the storage content of the nonvolatile memory 102 is a cassette having a power receiving function (response signal received) Starts the non-contact power supply by the power supply coil 92 immediately after the power is turned on. On the other hand, if the cassette has not been exchanged between the time when the power supply device 91 is turned off and the power is turned on again, and the cassette has no power reception function (no response signal is received), the power supply function is not activated. If the cassette has been exchanged between the time when the power supply device 91 is turned off and the power is turned on again, transmission of an inquiry signal is started as in the above embodiment. It is possible to save the trouble of transmitting an inquiry signal to a cassette that does not have a power receiving function or starting up a power feeding function.

  The power feeding device 91 is provided with the nonvolatile memory 102 for storing and holding the result of recognizing the cassette type. However, the result of recognizing the cassette type is transmitted from the power feeding device to the imaging control device or console, and the imaging control device or console is transmitted. The result of recognizing the cassette type in the volatile memory or the non-volatile memory may be stored and managed. The result of recognizing the type of cassette in a plurality of X-ray imaging systems existing in a plurality of imaging rooms can be collected and managed collectively by a console or the like.

  Instead of stopping the driving of the power supply device 91 when the start of X-ray irradiation is detected, it may be stopped before the imaging condition is set in the electronic cassette 21 via the imaging control device 23, for example. Good. Alternatively, the patient is set on the imaging table (when the patient stands in front of the imaging table 22a in the case of the standing imaging table 22a, or when the patient lies on the imaging table 22b in the case of the standing imaging table 22b) May be detected optically, mechanically, or electrically, and the driving of the power supply apparatus 91 may be stopped in response to this. A type without the irradiation detection sensor 25 can also be handled.

  In the above embodiment, image data is transmitted immediately after X-ray imaging. However, image data is transmitted after X-ray imaging, or image data is transmitted collectively after several imaging. There is also a case. In this case, when the X-ray imaging is completed, the power feeding device 91 is driven to charge the battery 41, and the driving of the power feeding device 91 is stopped again when image data is transmitted.

  When image data is transmitted using a communication method that is relatively resistant to electromagnetic noise, it is not always necessary to stop power supply when transmitting image data.

  It should be noted that the present invention is not limited to the above-described embodiment, and various configurations can be adopted without departing from the gist of the present invention.

  In the above embodiment, the electromagnetic induction method is described as an example of the non-contact power supply, but the magnetic resonance method that supplies power using an LC resonance circuit, the microwave power supply method that uses electromagnetic waves in the microwave band, Other non-contact power feeding methods such as an electric field coupling method in which power is exchanged between the plate electrodes, a laser power feeding method, an ultrasonic power feeding method, or the like may be adopted. In the electromagnetic induction method and the magnetic resonance method, for example, a feeding coil and a receiving coil are used as an antenna for transmitting and receiving an inquiry signal and a response signal as in the above-described embodiment. In other systems, a known antenna such as a planar antenna or a plate antenna can be used as the antenna.

  The X-ray imaging system 10 is not limited to the type installed in the imaging room of the hospital, but the type installed in the round-trip car, the X-ray source 13, the source control device 14, the electronic cassette 21, the imaging control device 23, etc. The present invention may be applied to a portable system capable of carrying out X-ray imaging by carrying it to a site requiring emergency medical treatment such as a disaster or the home of a patient receiving home medical care.

  In the above embodiment, the system that does not have the function of communicating between the X-ray generation apparatus and the X-ray imaging apparatus has been illustrated, but the present invention can also be applied to those having a communication function between the apparatuses. In this case, a sensor for detecting the start of irradiation is not necessary, and a synchronization signal for informing the start of X-ray irradiation is exchanged between the radiation source control device and the imaging control device, and the power supply function of the power supply device can be stopped using this as a trigger. .

  In the above-described embodiment, the electronic cassette and the imaging control device are described as separate components. Good. In addition, although image processing is performed by the console, it may be performed by a photographing control device. Further, the console may be integrated with the function of the imaging control device.

  The present invention can be applied not only to X-rays but also to imaging systems that use other radiation such as gamma rays.

DESCRIPTION OF SYMBOLS 10 X-ray imaging system 11 X-ray generator 12 X-ray imaging apparatus 21 Electronic cassette 22a, 22b (it has a power receiving function) Standing position, standing position imaging stand 23 Imaging control apparatus 24 Console 26 FPD
30a, 30b Holder 31 Antenna 41 Battery 45 Communication unit 46 Control circuit 52 Pixel 63 Signal processing circuit 81 Power reception coil 83 Power reception control unit 91, 101 Power supply device 92 Power supply coil 95 Full charge detection unit 96 Attachment / detachment detection unit 97 Power supply control unit 102 Non-volatile Memory

Claims (11)

An electronic cassette for radiography with a built-in battery,
A power transmission device that supplies power for charging in a non-contact manner to a battery built in the electronic cassette, and a signal transmission unit that transmits an inquiry signal for searching for the electronic cassette having a power receiving function to be powered; A signal receiving unit that receives a response signal to the inquiry signal from the electronic cassette, and a power supply device that has a control unit that causes the signal transmission unit to stop transmitting the inquiry signal when the signal receiving unit does not receive a response signal for a certain period of time When,
A radiation imaging apparatus comprising: an external control device that comprehensively controls the operation of the electronic cassette. Provided with an installation detection means for detecting whether an electronic cassette having a power receiving function or another cassette not having a power receiving function is installed at a specified location,
The radiographic apparatus according to claim 1, wherein the signal transmission unit starts transmission of an inquiry signal when installation is detected by the installation detection unit.   The radiographic imaging according to claim 2, wherein the installation detecting unit detects whether an electronic cassette having a power receiving function or another cassette not having a power receiving function is attached to a holder of the imaging table. apparatus.   The signal transmission means starts transmission of an inquiry signal when the reception means receives that the electronic cassette having a power reception function or another cassette having no power reception function has been turned on. Item 4. The radiographic apparatus according to any one of Items 1 to 3.   The signal transmission means starts transmission of an inquiry signal when the reception means has received that an imaging condition has been input from an external device using an electronic cassette having a power reception function or another cassette not having a power reception function. The radiation imaging apparatus according to claim 1, wherein the radiation imaging apparatus is characterized. A storage means for storing and holding the reception history of the response signal of the signal receiving means indicating whether the electronic cassette has a power receiving function or another cassette not having a power receiving function regardless of power on / off;
If the installation detection means does not detect the replacement of the cassette from the time the power is turned off to the time it is turned on again, the drive is controlled according to the storage contents of the storage means, and the installation detection means detects the replacement of the cassette from the time the power is turned off to the time the power is turned on again. 6. If so, the radiographic apparatus according to claim 2, wherein transmission of an inquiry signal by the signal transmission unit is started.   The radiation imaging apparatus according to claim 6, wherein the storage unit is provided in the external control device.   The radiographic apparatus according to claim 1, wherein the signal transmitting unit and the signal receiving unit are antennas, and transmit and receive electromagnetic waves as inquiry signals and response signals.   9. The power supply is stopped during radiographing with an electronic cassette and / or when receiving means that the radiographic image data is being transmitted from the electronic cassette to an external device is received. The radiation imaging apparatus according to one item.   The power supply is stopped when it is detected that the battery is fully charged or when it is detected that the electronic cassette is removed from the holder of the photographing stand. The radiographic apparatus according to the item.   11. The power feeding device is built in a holder of a photographing stand in which the electronic cassette having a power receiving function or another cassette not having a power receiving function is detachably accommodated. A radiation imaging apparatus according to claim 1.

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